INTEGRATED ASSESSMENT OF CLIMATE AND LAND USE CHANGE EFFECTS ON HYDROLOGY AND WATER QUALITY OF THE UPPER AND LOWER GREAT MIAMI RIVER

by MAXIMOV, IVAN A.

Abstract (Summary)

In the next 50-100 years it is likely to expect changes in climate and patterns of land-use activities in the Great Miami River basin in combination rather than individually. The ultimate goal of this research work was to apply the integrative approach in examining the potential impacts of hypothetically constructed climate and land-use changes on hydrological system and water quality of the Great Miami River. The research results show that dry climate scenarios paired with future land-use change scenario would reduce the annual flow of the Great Miami River and slightly increase the annual concentrations of phosphorus, total ammonia nitrogen and sum of nitrites and nitrates. The simulation results from combined wet climate scenario and land-use change scenario show a significantly larger increase in annual flow as well as greater presence of nutrients in the water. The study shows very high enrichments of phosphorus in the waters regardless whether it is a dry or wet scenario. In average, total orthophosphates annual concentrations in the Great Miami River showed a 40-50% increase compared to current conditions (from 0.45 mg/l to 0.65 mg/l), which is 2-3 times higher than the EPA suggested Water Quality Criteria for freshwaters. The results from hydrologic simulations indicate that if future climate changes to wet (+20% increase in precipitation), the volume of annual flow will increase in average by 70% compared to current conditions. This will result in a larger number and higher magnitudes of stormflows, which would cause more frequent devastating floods, elevating the risks of economic damages to the populated areas adjacent to the streams. The present study investigated the potential effects of Best Management Practices applications on water quantity and quality of the Stillwater River. Simulations of a number of BMPs showed their effectiveness in reducing pollutant concentrations in the stream, and, hence, improving the water quality. Finally, this dissertation has demonstrated that application of the GIS-based U.S EPA BASINS multipurpose environmental analysis system and HSPF model in concert is a very comprehensive water quality and quantity analysis tool. It can be useful in the implementations of long-term water resources management and development programs.